M4 Smarter Motorway – Response from RBWM
General
RBWM as part of the Thames Valley Local Economic Partnership is supportive of the M4 Smart Motorway project, as outlined in the TVB LEP Strategic Economic Plan.
The Council recognises that the scheme will provide additional traffic capacity and more reliable journey times on the M4, where congestion at peak times is spreading to other parts of the day. These improvements will help maintain the Borough’s connectivity across the Thames Valley and the wider area, as well as London and Heathrow airport.
However, RBWM fundamentally oppose the proposals for a third runway as part of Heathrow expansion due to the adverse environmental impact upon local residents, local businesses, institutions and the tourist trade and therefore would not support the M4 Smart Motorway scheme if it were being introduced to facilitate expansion at Heathrow.
Traffic Impact
Whilst the additional traffic capacity on the M4 motorway is to be supported, the Council remains concerned that the traffic impact on motorway junctions, approach roads as well as local roads has yet to be clearly identified. Mitigation measures to address these impacts needs to be considered and funding to implement appropriate measures needs to be identified.
Road Safety
Although the Council broadly supports the principals of the Smarter Motorway scheme, there are concerns about the full-time replacement of the hard shoulder with emergency refuge areas spaced a 2.5km intervals. A comparative safety assessment based on data from existing similar smart motorway arrangements would have supported this decision.
Construction Impact
Construction activity will need to be carefully managed in order to minimise impact upon adjacent residential properties. This includes the construction work compounds and traffic diversions from the motorway onto local roads during construction. Even in the absence of formal traffic diversions, we are concerned about traffic being displaced onto local roads in order to avoid the motorway during the construction phase. Construction related traffic also needs to be considered where this will have an impact upon local re roads.
The decision to provide offline new bridges at A330 Ascot Road, Monkey Island Lane, B376 Datchet Road and Ditton Court Road is welcomed as this will reduce traffic disruption during construction for local residents.
The timetable for construction of the scheme will conflict with other major construction projects in the area, including Crossrail, Western Rail Access to Heathrow, Maidenhead town centre developments and other committed development schemes across the Borough. Construction will therefore require careful co-ordination with the other on-going projects.
We remain concerned that the proposed phasing of project, with M4 J12 to J8/9 opening before J8/9 to J3 will result in additional traffic problems in the Maidenhead area.
The impact upon public rights of way during the construction phase also needs to be considered in order to minimise disruption.
Impact upon Air Quality
Bray/M4 AQMA
This AQMA was declared in 2009 and road traffic in the area is the dominant source of pollution.
NO2 concentrations near the M4 are the highest in the Borough and one of the highest within the area of the proposed scheme. The proposed scheme will increase motorway capacity by permanently converting the hard shoulder to a running lane creating a fourth lane. Emissions are predicted to increase and the distance between the traffic lane and sensitive receptors will be reduced.
Historically the rates of improvement in air quality and future year projections of declining concentrations have always been overestimated. Given the degree of uncertainty about the rate of improvement in air quality it is reasonable to adopt a precautionary approach and consider potential control measure.
We would not support the proposed scheme in its current form, with no control measures to reduce the air quality impact. In particular we recommend that Highways England consider noise barriers as a mean to improve air quality. It would be possible to improve the atmospheric dispersion of emissions from the M4 by increasing the height of the existing noise barriers in the area, which will also better contain the traffic noise from the new traffic lanes. The noise barriers would need to extend 350 metres to the west and 250 metres to the east of Windsor Road Overbridge. We would therefore suggest that the proposed scheme is an opportunity to mitigate the motorway air quality and noise impact in the area.
Noise and Vibration Impact
The decision to re-surface the whole of the motorway with low-noise surfacing, rather than just the sections of road to be widened, is welcomed.
However, the scheme would result in running lanes being moved closer to adjoining residential properties and other receptors. Therefore the Council would wish for Highways England to take the opportunity to implement mitigation measures in order to reduce the noise impact upon residents wherever possible.
Lighting Impact
The decision to not introduce lighting on sections of the motorway through RBWM that are presently unlit is welcomed on environmental grounds. The decision to introduce LED lighting that can be dimmed and controlled remotely in order to reduce environmental impact is also welcomed. We would nevertheless recommend that the road safety implications of any changes to the lighting are given due consideration.
Impact on Public Rights of Way
This is presently a footway/cycleway. We would wish to see this status retained and width improved to 3m
Thames Path National Trail
Existing widths should be maintained and opportunities for improvements progressed. Any closures should be kept short and convenient.
The Local Access Forum (LAF) Fast Response Team has examined the proposals for the M4 Smart Motorway and makes the following comments on behalf of the forum:
• Marsh Lane (Bridge 3 on consultation plan)
This forms part of an aspiration to improve horse riding in this area, in particular the forum is working towards a Multi-Use Route that will utilise this bridge. This area is heavily used by horse riders. Modifications are needed to this bridge to make it easier for use by horse riders which could easily be folded in to the design of the Highways England works, including building in a sufficient verge width and installing higher parapets on the bridge. The forum suggests that the BHS are consulted regarding the detailed design of the bridge.
• Datchet Footpath 1 (Bridge 11 on the plan)
This is used heavily by cyclists as well as walkers and the forum recommend that the opportunity is taken to improve the widths of the path to accommodate this use.
• General comments
The LAF note that there are approximately ten paths which cross the M4 in the borough. They request assurance from Highways England that these paths will be reinstated and put back to the same condition that they are now.